Feeding and management practices affect quality improvement in wild-caught edible crab (Cancer pagurus)

Summary

About 80% of the Norwegian landings of edible crab (Cancer pagurus) are females. Meat content is often poor also for hard-shelled crabs. Feeding has proved to increase the quality, however the feeding process is costly and should be as short as possible still providing the required product quality. The crab fishery season coincides with the females' reproduction period which affects the quality and body composition. Egg-carrying crabs are of no commercial value. The development of the gonads is therefore of great importance for a feeding management of crabs. A study was conducted to test if meat yield and quality increased over time in the peak season (September). Groups of females were fed a diet of saithe (Pollachius virens) fillet for 10, 24 and 33 days. An unfed reference group was killed, boiled and quality assessed at the start of the experimental period and compared with fed groups assessed in the same way at the termination of the feeding period. The improvement of quality traits was a continuous process, with a linear increase in total subjective impression, hepatopancreas lightness and gonadosomatic index (GSI) correlated with time of feeding or cumulative feed intake. Two different methods of inactivating the claws, banding and nicking, were compared during the feeding period. The treatments gave no difference in feed intake or external quality like lost legs and tips. Gonad and hepatopancreas were examined during several short experimental periods (3-4 weeks) expanding from just before until after the peak fishery season. In August, September and October/November GSI increased but no increase was seen in hepatosomatic index (HSI). Crabs with GSI between 15 and 18 (%) seemed to be close to spawning. In October/November 40% of the crabs spawned, in December 6.7%. No development in GSI was present in December but HSI increased for fed crabs. After the peak spawning period in October/November most of the remaining crabs do not start the onset of gonad development before the following year. Fed crab at this time of the year will be of a different body composition, with more hepatopancreas and less roe. Several factors may influence the economy in a feeding program. However, the short feeding period makes it possible to feed several batches in a year. In a growing market and with increasing knowledge in quality grading technology of live crabs, feeding of edible crab may be worthwhile in the future. (C) 2007 Elsevier B.V. All rights reserved.